分享-2023年资深前端进阶：前端登顶之巅-最全面的前端知识点梳理总结

*分享一个使用比较久的🪜

技术框架公司的选型：uni-app + uni-ui + vue3 + vite4 + ts

需求分析：微信小程序-uni-ui内容
1、创建一个自定义的下拉，支持多个内容的同时多选
2、定义好出入参数，支持回显内容等
3、绑定对应的v-model数据响应

1、代码信息

<template><view tabindex="1" ref="customSelectRef" class="uni-select" @click.stop="handleClickDiv"><view><template v-if="modelLabel.length"><span class="custom-tag" :key="index" v-for="(item, index) in modelLabel"><span>{{ item }}</span></span></template><span class="custom-tag" v-if="modelLabel.length && checkList.length - maxLength > 0">+ {{ checkList.length - maxLength }}</span><span v-if="!modelLabel.length" class="cus_placeholder">{{ placeholder }}</span><imgclass="icon-delete"v-if="modelLabel.length"@click.stop="handleRemove":src="'../../static/icons/delete.png'"/></view><transition><view class="cus_select_background" ref="cusSelectDropdown" v-if="isShowDropdown" @click="handleMemory"><view class="cus_tabs" :key="index" v-for="(item, index) in cusDataListChecked"><template v-if="item.children"><view class="cus_tabs_title">{{ item.text }}</view><view class="cus_tabs_body"><uni-data-checkboxmode="tag":multiple="multiple"v-model="item.checkList":localdata="item.children"@change="(val) => handleCheckedChange(val, item)"></uni-data-checkbox></view></template></view></view></transition><view v-if="isShowDropdown" class="custom_mask"></view></view>
</template><script setup lang="ts">
import { watch } from "vue";
import { toRaw } from "vue";
import { ref, onMounted, nextTick, onBeforeMount } from "vue";const props = withDefaults(defineProps<{dataSource: any;modelValue?: any;placeholder?: string;multiple?: boolean;maxLength?: number;}>(),{multiple: true,dataSource: [],modelValue: [],maxLength: 3,placeholder: "请选择",}
);const emit = defineEmits(["update:modelValue", 'change']);const customSelectRef = ref();const cusSelectDropdown = ref();const modelLabel = ref<Record<string, any>[]>([]);const checkList = ref<string[]>([]);const cusDataListChecked = ref<Record<string, any>[]>([]);const isShowDropdown = ref<boolean>(false);const isShowDownMemory = ref<boolean>(false);const handleClickDiv = () => {isShowDropdown.value = isShowDownMemory.value ? true : !isShowDropdown.value;isShowDownMemory.value = false;
};const handleMemory = () => {isShowDownMemory.value = true;
};const handleCheckedChange = (e: Record<string, any>, row: Record<string, any>) => {const { data } = e.detail;row.checkLabel = data.map((opt) => opt.text);getModelVal();
};const getModelVal = () => {const newValue = toRaw(cusDataListChecked.value);const newLabel = newValue.map((item) => item.checkLabel);const newModelVal = newValue.map((item) => item.checkList);const deconstructLabel = newLabel?.flat();const deconstructVal = newModelVal?.flat();modelLabel.value = deconstructLabel.slice(0, props.maxLength);checkList.value = deconstructVal;emit("update:modelValue", newModelVal);
};const handleRemove = (e) => {modelLabel.value = [];checkList.value = [];if (isShowDropdown.value) {isShowDropdown.value = false;}if (props.multiple) {cusDataListChecked.value = addCheckProperties(props.dataSource);}emit("update:modelValue", []);
};const addCheckProperties = (treeData) => {let result = [];result = JSON.parse(JSON.stringify(treeData));result.forEach((node) => {const child = node.children;node.checkList = [];node.checkLabel = [];if (child && child.length > 0) {addCheckProperties(child);}});return result;
};const findTreeChecked = (treeData) => {const newLabel = [];const val = toRaw(props.modelValue);treeData.forEach((node, index) => {if (node.children?.length) {const child = node.children;const bool = child.some((opt) => {const isExist = val[index] && val[index].includes(opt.value);isExist ? newLabel.push(opt.text) : void null;return isExist;});if (bool) {node.checkLabel = newLabel;node.checkList = val[index];}}});return treeData;
};watch(isShowDropdown, (newVal) => {emit('change', newVal, props.modelValue)
})onBeforeMount(() => {if (props.multiple) {cusDataListChecked.value = addCheckProperties(props.dataSource);}
});onMounted(async () => {await nextTick();if (props.multiple && props.modelValue.length) {cusDataListChecked.value = findTreeChecked(cusDataListChecked.value);getModelVal();}
});
</script><style lang="scss" scoped>
.uni-select {font-size: 14px;border: 1px solid #e5e5e5;box-sizing: border-box;border-radius: 4px;padding: 0 5px 0 10px;position: relative;display: flex;user-select: none;flex-direction: row;align-items: center;border-bottom: solid 1px #e5e5e5;width: 100%;flex: 1;height: 35px;position: relative;
}.cus_placeholder {color: #6a6a6a;font-size: 12px;
}.icon-delete {position: absolute;width: 18px;height: 18px;right: 5px;margin-top: 3.5px;z-index: 10;
}.cus_select_background {width: 95vw;max-height: 260px;box-sizing: border-box;border-radius: 4px;font-size: 13px;color: #606266;background: #ffffff;border: 1px solid #e4e7ed;position: absolute;top: 40px;left: 0px;padding: 5px 8px;z-index: 10;
}.cus_tabs {margin-bottom: 8px;.cus_tabs_title {font-weight: 600;margin-bottom: 4px;}.cus_tabs_body {margin-left: 12px;}
}.custom-tag {color: #909399;display: inline-flex;justify-content: center;align-items: center;height: 24px;padding: 0 9px;line-height: 1;border-radius: 4px;white-space: nowrap;font-size: 13px;margin-right: 5px;background-color: #f0f2f5;
}.custom_mask {position: fixed;top: 0;bottom: 0;left: 0;right: 0;z-index: 1;display: flex;justify-content: center;align-items: center;
}
</style>

2、使用api介绍

1、树形结构入参：dataSource=[{ ext: "服务器状态", children: [{ text: "在线", value: 0}]}]，
2、标签引用：<ivuSelect :maxLength="2" ref="ivuSelectRef" v-model="customSelect" :dataSource="deviceDataList" style="width: 100%; margin-left: 5px" />
3、相关api说明文档在文章底部

参数	说明	类型	默认值	必填项
dataSource	[{}]-label,value;树形结构	Array[]	[]	是
modelValue	当前选中项内容	Array	[]	否
placeholder	输入框内容	String	请输入	否
multiple	是否开启多选	Boolean	false	否
maxLength	输入框最大标签长度	Number	3	否